Protection of satellite tobacco necrosis virus ribonucleic acid by wheat germ 40S and 80S ribosomes

Abstract

Wheat germ ribosomes combine with the AUG codon at positions 30-32 from the 5'' terminus of in vitro radioiodinated satellite tobacco necrosis virus (STNV) RNA to form initiation complexes that protect specific regions of the RNA from attack by RNases. Wheat germ 80S ribosomes convey partial protection to a region 20-52 nucleotides from the 5'' terminus of STNV RNA and convey protection against high levels of RNases to a region of 20-44 nucleotides from the 5'' terminus of STNV RNA. Wheat germ 40S ribosomes convey partial protection to a region 3-52 nucleotides from the 5'' terminus of STNV RNA and convey protection against high levels of RNases to a region of 10-47 nucleotides from the 5'' terminus of STNV RNA. Characterization of these levels of protection against attack by specific RNases establishes that wheat germ 40S and 80S ribosomes from initiation complexes with a linear conformation of STNV RNA lacking the 5''-terminal stem and loop anticipated by Leung and co-workers for the 5'' terminus of STNV RNA.